The present invention relates to manufactured articles made of at least two different materials, including filler materials to provide individual material properties, and more particularly relates to wholly or partially hollow members made by three-dimensional blow molding comprising at least two different materials having individual material properties.
Three-dimensional blow molding is a known technique in the art for producing articles having tri-axially oriented configured shapes with hollow interiors. Within this art area, it is known to include multi-segmented parisons, or laminated parisons in order to produce multi-layered molded articles. While it has been known in the traditional biaxial (or two dimensional) blow molding and the injection molding arts to use more than one molding resin in order to achieve the abovementioned multiple layers or segments, the relatively new art area of three-dimensional blow molding has introduced a whole new set of problems in terms of the selection, compatibility, adhesion, and formability of molded articles when trying to incorporate segmented or layered materials.
With the desire to reduce the number of parts assembled into an automobile or other manufactured items, it is preferable to produce and process manufactured articles which are formed of many materials in one article, rather than be assembled out of numerous parts made of the individually desired materials. For example, an airflow tube used in automotive applications used to be comprised of rigid plastic portions, flanged to a soft rubber bellows portion for flexibility, and attached via hose clamps to other automotive components.
Automobile manufacturers are desirous of purchasing an airflow tube that already has all of these material components in one unit which can be assembled into a car much more easily. In addition, the automobile manufacturer has found that it is much less expensive to stock, inventory, catalog, and approve the vendors for numerous articles. Rather than dealing with multiple parts, it is much easier for automotive manufacturers to stock, inventory and catalog a single part. Furthermore, they only need to qualify a single vendor, rather than numerous vendors.
Consequently, three-dimensional blow molding has been of great interest to the automobile manufacturers because of their ability to form complex shapes without wasting material, although the cycling time may be too long for advantageous production of basic plastic parts. However, new techniques for decreasing the cycling time are in progress, and the inclusion of multi-property materials may reduce the overall production times when compared to the production of a multiple of parts assembled together thereafter.
Standard three-dimensional or triaxially oriented blow molding processes are known in the art. A parison or tube is formed by the injection of a plasticized material around a hollow mandrel. While the material is still molten and still on the mandrel, it is transferred into a blowing mold where air is used to inflate it. In three-dimensional blow molding, the parison is placed or directed into a three-dimensional mold prior to being cured into a substantially rigid or stiff element.
Although it is known to produce three dimensionally blow molded multi-segmented hollow parts that incorporate hard and soft materials, there are many aspects of incorporating new and different materials into the length, walls, and portions of the hollow parts which are not known to have been explored. It is this aspect of utilizing multiple materials having varying properties which is the subject of the instant invention.
It is, therefore, desirable to provide a blow molding process and resultant article that will achieve the goals mentioned above. The desirable properties that are addressed by the present invention include electrically conducting and insulating properties, magnetically oriented materials, thermally dissipative or conducting properties, shrinkage factor differences, coloring and pigmented differences, varying compressive and tensile strengths, vapor permeability, chemical inertness and reactivity coefficients, textures, catalytic surfacing effects among other new properties.
Examples of articles which can be made by the present process invention are automotive parts including air flow tubes, console lids, knee bolsters, instrument panel components, fire walls with HVAC ducts already in place, radiator gaskets for high temperature resins with ceramic filler components, HVAC valves, numerous under the hood items such as manifolding, fuel injection systems, and fuel tanks which can be blow molded with rock shields integral to the unit. Non-automotive parts can include computer cases, utilizing the electrically conductive materials, thermally dissipative and magnetically insulative materials; as well as electronic components such as radios, cable TV boxes and the like. Non-electronic applications may include water filter casings which would utilize the features of anti-microbial inclusions within the materials to ward off germs forming on the surface in contact with the water. The other applications are too numerous to mention.
In the manufacture of the above mentioned blow molded examples, the present invention seeks to provide an arrangement for various materials longitudinally, vertically, and regionally throughout the length of the parison being made and directed into the three-dimensional blow mold prior to curing and setting. The present invention can also find utility in the field of injection molding, merely translating the various materials into the materials being injected.
The different materials can include:
1. All resins suitable for injection molding, three dimensional blow molding, biaxial blow molding and vacuum molding, including, but not limited to polyesters, polypropylene, polyethylene, polyester terphthalate, butadiene-styrene copolymers, polyamides, ethylene-vinyl-alcohol copolymer, polyethylene napthaphthalate, thermoplastic and thermosetting resins, polybutylene terephthalate, polyoxymethylenes, polycarbonates, polyphenylene, polyphenylene sulfides, polyphenylene oxides, polymethylmethacrylate, polyethylene-terephthalate, polyvinylidenechloride, polymethylpentene-1, nylon 6, nylon 66, and others;
2. All naturally occurring and all manufactured ceramics, including, but not limited to, ceramics selected from the group consisting of silicon nitride, silicon carbide, alumina, boron carbide, tungsten carbide, and other carbides, nitrides and oxides of various metals to be chosen for their various properties, whether in powder, whisker, low aspect talc form, or any other form which can be incorporated into the parison, either by itself if it can be slip casted, injection molded or extruded, or along with a resin in order to be incorporated into the bulk of the parison material;
3. Various other particulate materials including clays such as kaolin, cordierite, mullite; metal flakes such as iron filings, steel chips, magnetic filings, magnetic particles and various other surface enhancing metal particulates; pulverized road construction particulates including stone chips, crushed slag, crushed concrete, cracked and crushed heavy road tars, and the like; crumbed rubber tires, densified foam chips, recycled materials to be used as filler or as property enhancers, such as fibers from cardboard and other paper products, crumbed soda pop bottles; and other filler materials to add inexpensively to the volume of material or to impart strength such as glass fibers for reinforcement, silicon carbide whiskers for added strength and thermal resistivity.
The instant invention also calls for the optional use of an adhesion gas, such as a sulfur-containing sulfonation gas, so that the materials can be molecularly adhered to one another to form a very strong bond via the adhesion gas application during the xe2x80x9cblowxe2x80x9d portion of the blow molding operation. Thereafter, the part may be subjected to a neutralizing agent, in order to finish the part.
Articles resulting from the above process are composed of multiple materials, and may include numerous wholly or partially hollow parts such as various automotive parts, including air flow tubes. Examples of the resulting articles follow in the Examples section below.
Therefore, the advantages of the present invention are fully realized when practicing the process of the present invention and the articles resulting therefrom.